title: Siganus oramin recombinant L-amino acid oxidase is lethal to Cryptocaryon irritans.
abstract: A novel antimicrobial and antiparasitic protein (APP/SR-LAAO) isolated from serum of the rabbitfish (Siganus oramin) was confirmed to be lethal to Cryptocaryon irritans, an important marine parasitic ciliate that causes marine white spot disease in a variety of wild and cultured fish. In this study, a recombinant SR-LAAO (rSR-LAAO) was expressed on a large scale in Escherichia coli Rosetta-gami™(DE3)pLysS cells. rSR-LAAO was expressed as an inactive form in the inclusion bodies. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that after purification, refolding and ultrafiltration, rSR-LAAO had a significantly cytotoxic effect on C. irritans theronts. Using light microscopy, scanning electron microscopy and fluorescence microscopy, we found that theronts rapidly became weakly motile, cilia became detached, cells became rounded, membranes eventually lysed in different cell positions and cytoplasmic contents leaked out of the cell. These results suggested the recombinant SR-LAAO was significantly lethal to C. irritans and the death process of the parasite incubated with rSR-LAAO was remarkably similar compared to the SR-LAAO group as reported earlier.
authors.affiliation: Key Laboratory for Aquatic Products Safety of Ministry of Education, State Key Laboratory of Biocontrol, The School of Life Sciences, Sun Yat-sen University, 135 Xingang West Street, Haizhu District, Guangzhou, Guangdong Province 510275, PR China.
authors.forename: Ruijun
authors.initials: R
authors.lastname: Li
authors.forename: Xueming
authors.initials: X
authors.lastname: Dan
authors.forename: Anxing
authors.initials: A
authors.lastname: Li
mesh_terms: D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D016798:Ciliophora / Q000276:immunology*; D016770:Ciliophora Infections / Q000201:enzymology / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D004926:Escherichia coli / Q000235:genetics; D005393:Fish Diseases / Q000201:enzymology / Q000276:immunology* / Q000469:parasitology; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D007113:Immunity, Innate; D050830:L-Amino Acid Oxidase / Q000235:genetics* / Q000378:metabolism; D013058:Mass Spectrometry / Q000662:veterinary; D008855:Microscopy, Electron, Scanning / Q000662:veterinary; D008856:Microscopy, Fluorescence / Q000662:veterinary; D010473:Perciformes; D011994:Recombinant Proteins
chemical_list: D029941:Fish Proteins; D011994:Recombinant Proteins; D050830:L-Amino Acid Oxidase
keywords: Cryptocaryon irritans; Recombinant L-amino acid oxidase; Siganus oramin